First Prize in the Stone Concrete and Cement Contest. But — and this is an important but — vermiculite is more compressible and less porous than perlite, giving vermiculite higher water-holding capacity when it’s used as a planting medium. Fix the board permanently on top of the four paving slabs with some fire cement applied with a tiling comb and then press it down firmly. Vermiculite in Pizza Ovens. Fantastically documented! High amount of asbestos may cause health illness and for that reason vermiculite with high amount of asbestos should be avoided as insulator. The thickness of vermiculite mixer will be three to four inch because this thickness is enough to prevent heat loss hearth inside of pizza oven. Number the bricks if you are worried about mixing up the bricks during cutting. In your description of the first layer over the fitness ball, you mention to make the cement/vermiculite layer approximately 20 centimeters thick. Is vermiculite is a problem as insulator? To make the dome you will need to construct a simple jig to support the gym ball. Bed the brick arch in using the arch jig for support and using a standard 4:1 mortar mix. You will enjoy cooking (and eating) tasty stone baked pizzas that cook in seconds as much as you will enjoy the satisfaction of having made the oven yourself from scratch. Wrap your flue pipe with a layer of cardboard. Don't soak it - the goal here is to slow down the curing process by not letting it dry completely. When vermiculite is heated, asbestos will be released and mixed with air. Use the brick arch jig template you made earlier to get the rough size for the door. After one week, uncover the dome and allow it to fully cure and dry out. 39,266. They are very thick, strong, solid slabs - perfect for the base. The jig is basically a crude table with a 700mm circle cut out of the middle. I used a staplegun with long 30mm staples. This took my dome about one month to cure fully. I appreciate your insight of using vermiculite in a pizza oven dome. Four parts building sand to one part Portland cement. For under hearth insulation, thick layer of vermiculite insulator is applied. Six more breeze blocks were placed on the top horizontally to form a roof to the base. For an oven this size, clear an area larger than your intended base. Lightweight breeze blocks (as they are called in the UK) were used for the base walls of structure because they are easy to shape, cut to size and handle. You can’t nor shouldn’t trust that someone else, government agency or corporate interest is looking out for your best interest. Thank you for your vote! Introduction: Vermiculite, Gym Ball Dome, Wood Fired Pizza Oven. Thus contaminated vermiculite cause health problem. Go entertain your friends and family! You can get the size of the semicircle from the scale plan PDF attached to step 3. - good luck with it all! This design serves the needs of both the pizza baker and the bread baker, by having an inner layer of material with a high thermal mass, and a surrounding heat-resistant insulation layer. When dome gets hot inside, it will be hot outside gradually. I added an extra brick on the top of the arch as a design feature / somewhere to put a glass of wine :). Light another curing fire... no high temps though yet. This will cause different problems like lung cancer and mesothelioma. Reply The Montana mine you mention produced 70% of the US supply and 80% of the worlds supply of Vermiculite at peak production and it is estimated that 35 million US homes contain asbestos contaminated vermiculite insulation. I built this pizza oven for my family instead of buying a similar one for at least £700 ($900). Vermiculite is a heat proof insulation material typically used in chimney backfills and is cheap and easy to find in your local builders yard. Did you make this project? Vermiculite, Gym Ball Dome, Wood Fired Pizza Oven. Be patient - don't rush or skip this step or be tempted to light a big fire as the oven may crack if you go too hot too soon. Release your dried vermiculite dome from the jig by deflating the gym ball and passing a knife around the bottom edge of the dome. did you find any issues with sticking dough?Also other builders suggest a door height of approx 60-65% of the dome height, was this something you considered or built based on ease of opening? This expanded vermiculite is light-weight, odorless, fire resistant and absorbent. NICE! Your jig looks perfect for the job! I used a total of 32 breeze blocks for the walls and eight paving slabs for the top and bottom. A cleaner finish would be achieved with an angle grinder if you have one. Is vermiculite insulation used for pizza oven? Pin the blanket down by stretching chickenwire over the whole dome. Go ahead and plaster the front and sides of the base whilst you are at it. I hope you enjoy making your own wood fired pizza oven! Aim for about a 10mm coat. Vermiculite insulation for pizza oven dome. My board did crack as you can see in the picture - it's no big deal. Cut out an approximate chimney hole roughly where the the flue will go. These ovens can be constructed fairly easily at home with exfoliated vermiculite and other refractory materials such as fire bricks. Looking forward to getting started with the next step! Share it with us! 310. Vermiculite for gardening will be safe but if in doubt, wear a mask, vermiculite is quite dusty anyway so just wear a mask would be my advice.Remember that anything you read on the internet may or may not be correct - Including my own advise above. Some houses built in the US during that era were insulated with this specific vermiculite from that specific mine. Pack the mould with more vermiculite mix (same recipe) and allow to cure for a week or so. Next, bond the fire bricks down with another thin layer of fire cement. That's six parts plastering sand, one part Portland cement and one part hydrated lime. Trim your house bricks with a bolster and hammer or an angle grinder to match the contour of the dome as closely as possible. Thanks again for writing up this instructable and posting it. Featured. Start loading up the sides of the gym ball with the first layer of vermiculite cement mixture with your hands, clump by clump. Whenever handling dust producing material, a cheap respirator, properly filtered and fitted for the application is always a safe bet. When vermiculite is heated, it gets expanded and creates some pockets to prevent heat conduction. When I made my dome, I also made some test lumps of vermiculite cement mix so that I could see how the curing and drying process was going. You are just trying to get the dome slightly warm. I have no bricklaying experience and it wasn't to difficult - just use a spirit level all the time to check that it is all straight. They are both silicates i’ll give you that… As i have mentioned in the comments: Vermiculite was once mined from a mine which also contained asbestos. Vermiculite is mixed with Portland cement as a ratio of 5:1. How does vermiculite with high asbestos cause health problem.